modules: define few undefined but referenced symbols

These are referenced by the "x module not available" message in
modules/Kconfig, but were only defined in the module, were generating an
undefined symbol warning when running CI compliance with no modules.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

modules/Kconfig

@@ -16,6 +16,7 @@ comment "Optional modules. Make sure they're installed, via the project manifest
 
 source "modules/Kconfig.altera"
 source "modules/Kconfig.atmel"
+source "modules/Kconfig.chre"
 source "modules/Kconfig.cmsis"
 source "modules/Kconfig.cypress"
 source "modules/Kconfig.eos_s3"
@@ -28,6 +29,7 @@ source "modules/Kconfig.mcux"
 source "modules/Kconfig.microchip"
 source "modules/Kconfig.nuvoton"
 source "modules/Kconfig.open-amp"
+source "modules/Kconfig.picolibc"
 source "modules/Kconfig.s32"
 source "modules/Kconfig.silabs"
 source "modules/Kconfig.simplelink"

modules/Kconfig.chre

@@ -0,0 +1,5 @@
+# Copyright 2023 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config ZEPHYR_CHRE_MODULE
+	bool

modules/Kconfig.picolibc

@@ -0,0 +1,5 @@
+# Copyright 2023 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config ZEPHYR_PICOLIBC_MODULE
+	bool

modules/liblc3/Kconfig

@@ -1,6 +1,9 @@
 # Copyright (c) 2022 Bose Corporation
 # SPDX-License-Identifier: Apache-2.0
 
+config ZEPHYR_LIBLC3_MODULE
+	bool
+
 config LIBLC3
 	bool "liblc3 Support"
 	depends on FPU